EX. UK-16 Time History Analysis for Forcing Function and Ground Motion
Dynamic Analysis (Time History) is performed for a 3 span beam with concentrated and distributed masses. The structure is subjected to forcing function
and ground motion
loading. The maxima of joint displacements, member end forces and support reactions are determined.
This problem is installed with the program by default to C:\Users\Public\Public Documents\STAAD.Pro 2024\Samples \Sample Models\UK\UK-16 Time History Analysis for Forcing Function and Ground Motion.STD when you install the program.
Where:
- L1 = 1.2 m
STAAD PLANE EXAMPLE FOR TIME HISTORY ANALYSIS
Every input file has to start with the word STAAD
. The term PLANE
signifies that the structure is a plane frame.
UNITS CMS KNS
Specifies the units to be used.
JOINT COORDINATES
1 0.0 0.0 0.0
2 0.0 120.0 0.0
3 0.0 240.0 0.0
4 0.0 360.0 0.0
Joint number followed by the X, Y and Z coordinates are specified above.
MEMBER INCIDENCES
1 1 2 3
Incidences of members 1 to 3 are specified above.
MEMBER PROPERTIES
1 2 3 PRIS AX 100.0 IZ 833.33
All the members have PRISMATIC
property specification. Since this is a plane frame, Area of cross section (AX
) and Moment of Inertia (IZ
) about the Z axis are adequate for the analysis.
SUPPORTS
1 4 PINNED
Pinned supports are located at nodes 1 and 4.
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 2850
POISSON 0.17
DENSITY 25e-006
ALPHA 5e-006
DAMP 0.05
G 925
TYPE CONCRETE
STRENGTH FCU 2.75
END DEFINE MATERIAL
CONSTANTS
MATERIAL CONCRETE ALL
The DEFINE MATERIAL
command is used to specify material properties and the CONSTANT
is used to assign the material to all members.
UNIT NEWTON METER
DEFINE TIME HISTORY
TYPE 1 FORCE
0.0 –20.0 0.5 100.0 1.0 200.0 1.5 500.0 2.0 800.0 2.5 500.0 3.0 70.0
TYPE 2 ACCELERATION
0.0 0.1 0.5 –0.25 1.0 –0.5 1.5 –0.9 2.0 –1.3 2.5 –1.0 3.0 –0.7
ARRIVAL TIMES
0.0
DAMPING 0.075
There are two stages in the command specification required for a time history analysis. The first stage is defined above. First the characteristics of the time varying load are provided. The loading type may be a forcing function (vibrating machinery) or ground motion (earthquake). The former is input in the form of time-force pairs while the latter is in the form of time-acceleration pairs. Following this data, all possible arrival times for these loads on the structure as well as the modal damping ratio are specified. In this example, the damping ratio is the same (7.5%) for all modes.
LOAD 1 STATIC LOAD
MEMBER LOAD
1 2 3 UNI GX 500.0
Load case 1 above is a static load. A uniformly distributed force of 500 Newton/m acts along the global X direction on all 3 members.
LOAD 2 TIME HISTORY LOAD
SELFWEIGHT X 1.0
SELFWEIGHT Y 1.0
JOINT LOAD
2 3 FX 4000.0
TIME LOAD
2 3 FX 1 1
GROUND MOTION X 2 1
This is the second stage in the command specification for time history analysis. This involves the application of the time varying load on the structure. The masses that constitute the mass matrix of the structure are specified through the selfweight and joint load commands. The program will extract the lumped masses from these weights. Following that, both the TIME LOAD
and GROUND MOTION
are applied simultaneously.
TIME LOAD
and GROUND MOTION
both act on the structure at the same time. The Time load command is used to apply the Type 1 force, acting in the global X direction, at arrival time number 1, at nodes 2 and 3. The Ground motion, namely, the Type 2 time history loading, is also in the global X direction at arrival time 1.
PERFORM ANALYSIS
The above command initiates the analysis process.
PRINT JOINT DISPLACEMENTS
During the analysis, the program calculates joint displacements for every time step. The absolute maximum value of the displacement for every joint is then extracted from this joint displacement history. So, the value printed using the above command is the absolute maximum value for each of the six degrees of freedom at each node.
UNIT KNS METER
PRINT MEMBER FORCES
PRINT SUPPORT REACTION
The member forces and support reactions too are calculated for every time step. For each degree of freedom, the maximum value of the member force and support reaction is extracted from these histories and reported in the output file using the above command.
FINISH
Input File
STAAD PLANE EXAMPLE FOR TIME HISTORY ANALYSIS
UNITS CMS KNS
JOINT COORDINATES
1 0.0 0.0 0.0
2 0.0 120.0 0.0
3 0.0 240.0 0.0
4 0.0 360.0 0.0
MEMBER INCIDENCES
1 1 2 3
MEMBER PROPERTIES
1 2 3 PRIS AX 100.0 IZ 833.33
SUPPORTS
1 4 PINNED
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 2850
POISSON 0.17
DENSITY 25e-006
ALPHA 5e-006
DAMP 0.05
G 925
TYPE CONCRETE
STRENGTH FCU 2.75
END DEFINE MATERIAL
CONSTANTS
MATERIAL CONCRETE ALL
UNIT NEWTON METER
DEFINE TIME HISTORY
TYPE 1 FORCE
0.0 -20.0 0.5 100.0 1.0 200.0 1.5 500.0 2.0 800.0 2.5 500.0 3.0 70.0
TYPE 2 ACCELERATION
0.0 0.1 0.5 -0.25 1.0 -0.5 1.5 -0.9 2.0 -1.3 2.5 -1.0 3.0 -0.7
ARRIVAL TIMES
0.0
DAMPING 0.075
LOAD 1 STATIC LOAD
MEMBER LOAD
1 2 3 UNI GX 500.0
LOAD 2 TIME HISTORY LOAD
SELFWEIGHT X 1.0
SELFWEIGHT Y 1.0
JOINT LOAD
2 3 FX 4000.0
TIME LOAD
2 3 FX 1 1
GROUND MOTION X 2 1
PERFORM ANALYSIS
PRINT JOINT DISPLACEMENTS
UNIT KNS METER
PRINT MEMBER FORCES
PRINT SUPPORT REACTION
FINISH
PAGE NO. 1
****************************************************
* *
* STAAD.Pro 2023 *
* Version 23.00.03.** *
* Proprietary Program of *
* Bentley Systems, Inc. *
* Date= JUL 4, 2024 *
* Time= 11:19:54 *
* *
* Licensed to: Bentley Systems Inc *
****************************************************
1. STAAD PLANE EXAMPLE FOR TIME HISTORY ANALYSIS
INPUT FILE: D:\Documentation\STAAD.Pro\_Automated_Py\output\2024-07-04\SPro_Output_Input_Files\Sample .. .STD
2. UNITS CMS KNS
3. JOINT COORDINATES
4. 1 0.0 0.0 0.0
5. 2 0.0 120.0 0.0
6. 3 0.0 240.0 0.0
7. 4 0.0 360.0 0.0
8. MEMBER INCIDENCES
9. 1 1 2 3
10. MEMBER PROPERTIES
11. 1 2 3 PRIS AX 100.0 IZ 833.33
12. SUPPORTS
13. 1 4 PINNED
14. DEFINE MATERIAL START
15. ISOTROPIC CONCRETE
16. E 2850
17. POISSON 0.17
18. DENSITY 25E-006
19. ALPHA 5E-006
20. DAMP 0.05
21. G 925
22. TYPE CONCRETE
23. STRENGTH FCU 2.75
24. END DEFINE MATERIAL
25. CONSTANTS
26. MATERIAL CONCRETE ALL
27. UNIT NEWTON METER
28. DEFINE TIME HISTORY
29. TYPE 1 FORCE
30. 0.0 -20.0 0.5 100.0 1.0 200.0 1.5 500.0 2.0 800.0 2.5 500.0 3.0 70.0
31. TYPE 2 ACCELERATION
32. 0.0 0.1 0.5 -0.25 1.0 -0.5 1.5 -0.9 2.0 -1.3 2.5 -1.0 3.0 -0.7
33. ARRIVAL TIMES
34. 0.0
35. DAMPING 0.075
36. LOAD 1 STATIC LOAD
37. MEMBER LOAD
38. 1 2 3 UNI GX 500.0
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 2
39. LOAD 2 TIME HISTORY LOAD
40. SELFWEIGHT X 1.0
41. SELFWEIGHT Y 1.0
42. JOINT LOAD
43. 2 3 FX 4000.0
44. TIME LOAD
45. 2 3 FX 1 1
46. GROUND MOTION X 2 1
47. PERFORM ANALYSIS
P R O B L E M S T A T I S T I C S
-----------------------------------
NUMBER OF JOINTS 4 NUMBER OF MEMBERS 3
NUMBER OF PLATES 0 NUMBER OF SOLIDS 0
NUMBER OF SURFACES 0 NUMBER OF SUPPORTS 2
Using 64-bit analysis engine.
SOLVER USED IS THE IN-CORE ADVANCED MATH SOLVER
TOTAL PRIMARY LOAD CASES = 2, TOTAL DEGREES OF FREEDOM = 8
TOTAL LOAD COMBINATION CASES = 0 SO FAR.
***NOTE: MASSES DEFINED UNDER LOAD# 2 WILL FORM
THE FINAL MASS MATRIX FOR DYNAMIC ANALYSIS.
MORE MODES WERE REQUESTED THAN THERE ARE FREE MASSES.
NUMBER OF MODES REQUESTED = 6
NUMBER OF EXISTING MASSES IN THE MODEL = 4
NUMBER OF MODES THAT WILL BE USED = 4
*** EIGENSOLUTION : ADVANCED METHOD ***
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 3
CALCULATED FREQUENCIES FOR LOAD CASE 2
MODE FREQUENCY(CYCLES/SEC) PERIOD(SEC)
1 3.087 0.32397
2 11.955 0.08365
3 443.457 0.00226
4 768.090 0.00130
MODAL WEIGHT (MODAL MASS TIMES g) IN NEWT GENERALIZED
MODE X Y Z WEIGHT
1 8.600000E+03 0.000000E+00 0.000000E+00 8.600000E+03
2 3.840329E-24 0.000000E+00 0.000000E+00 8.600000E+03
3 0.000000E+00 6.000000E+02 0.000000E+00 6.000000E+02
4 0.000000E+00 1.748000E-27 0.000000E+00 6.000000E+02
MASS PARTICIPATION FACTORS
MASS PARTICIPATION FACTORS IN PERCENT
--------------------------------------
MODE X Y Z SUMM-X SUMM-Y SUMM-Z
1 100.00 0.00 0.00 100.000 0.000 0.000
2 0.00 0.00 0.00 100.000 0.000 0.000
3 0.00 100.00 0.00 100.000 100.000 0.000
4 0.00 0.00 0.00 100.000 100.000 0.000
A C T U A L MODAL D A M P I N G USED IN ANALYSIS
MODE DAMPING
1 0.07500000
2 0.07500000
3 0.07500000
4 0.07500000
TIME STEP USED IN TIME HISTORY ANALYSIS = 0.00139 SECONDS
NUMBER OF MODES WHOSE CONTRIBUTION IS CONSIDERED = 2
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 4
WARNING-NUMBER OF MODES LIMITED TO A FREQUENCY OF 360.0 DUE TO THE DT VALUE ENTERED.
TIME DURATION OF TIME HISTORY ANALYSIS = 3.000 SECONDS
NUMBER OF TIME STEPS IN THE SOLUTION PROCESS = 2160
48. PRINT JOINT DISPLACEMENTS
BASE SHEAR UNITS ARE -- NEWT METE
MAXIMUM BASE SHEAR X= -2.777266E+03 Y= 0.000000E+00 Z= 0.000000E+00
AT TIMES 2.054167 0.000000 0.000000
JOINT DISPLACE
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 5
JOINT DISPLACEMENT (CM RADIANS) STRUCTURE TYPE = PLANE
------------------
JOINT LOAD X-TRANS Y-TRANS Z-TRANS X-ROTAN Y-ROTAN Z-ROTAN
1 1 0.0000 0.0000 0.0000 0.0000 0.0000 -0.0041
2 0.0000 0.0000 0.0000 0.0000 0.0000 -0.0084
2 1 0.4002 0.0000 0.0000 0.0000 0.0000 -0.0020
2 0.8420 0.0000 0.0000 0.0000 0.0000 -0.0042
3 1 0.4002 0.0000 0.0000 0.0000 0.0000 0.0020
2 0.8420 0.0000 0.0000 0.0000 0.0000 0.0042
4 1 0.0000 0.0000 0.0000 0.0000 0.0000 0.0041
2 0.0000 0.0000 0.0000 0.0000 0.0000 0.0084
************** END OF LATEST ANALYSIS RESULT **************
49. UNIT KNS METER
50. PRINT MEMBER FORCES
MEMBER FORCES
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 6
MEMBER END FORCES STRUCTURE TYPE = PLANE
-----------------
ALL UNITS ARE -- KNS METE (LOCAL )
MEMBER LOAD JT AXIAL SHEAR-Y SHEAR-Z TORSION MOM-Y MOM-Z
1 1 1 0.00 0.90 0.00 0.00 0.00 -0.00
2 0.00 -0.30 0.00 0.00 0.00 0.72
2 1 0.00 1.39 0.00 0.00 0.00 0.00
2 0.00 -1.39 0.00 0.00 0.00 1.67
2 1 2 0.00 0.30 0.00 0.00 0.00 -0.72
3 0.00 0.30 0.00 0.00 0.00 0.72
2 2 0.00 0.00 0.00 0.00 0.00 -1.67
3 0.00 0.00 0.00 0.00 0.00 1.67
3 1 3 0.00 -0.30 0.00 0.00 0.00 -0.72
4 0.00 0.90 0.00 0.00 0.00 0.00
2 3 0.00 -1.39 0.00 0.00 0.00 -1.67
4 0.00 1.39 0.00 0.00 0.00 0.00
************** END OF LATEST ANALYSIS RESULT **************
51. PRINT SUPPORT REACTION
SUPPORT REACTION
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 7
SUPPORT REACTIONS -UNIT KNS METE STRUCTURE TYPE = PLANE
-----------------
JOINT LOAD FORCE-X FORCE-Y FORCE-Z MOM-X MOM-Y MOM Z
1 1 -0.90 0.00 0.00 0.00 0.00 0.00
2 -1.39 0.00 0.00 0.00 0.00 0.00
4 1 -0.90 0.00 0.00 0.00 0.00 0.00
2 -1.39 0.00 0.00 0.00 0.00 0.00
************** END OF LATEST ANALYSIS RESULT **************
52. FINISH
*********** END OF THE STAAD.Pro RUN ***********
**** DATE= JUL 4,2024 TIME= 11:19:56 ****
EXAMPLE FOR TIME HISTORY ANALYSIS -- PAGE NO. 8
************************************************************
* For technical assistance on STAAD.Pro, please visit *
* http://www.bentley.com/en/support/ *
* *
* Details about additional assistance from *
* Bentley and Partners can be found at program menu *
* Help->Technical Support *
* *
* Copyright (c) Bentley Systems, Inc. *
* http://www.bentley.com *
************************************************************